The primary goal of this grant is to allow me to obtain the broad scientific education necessary for me to make a significant contribution to auditory neuroscience. As a Pediatric Otolaryngologist, I am extremely aware of the morbidity caused by human hearing dysfunction. Although I have been active in research during my clinical training, I do not have all of the neuroscience, developmental and molecular training background that I will need to be significant independent contributor to hearing research. This training grant is structured to allow me to obtain that training. As part of this training, I will continue my research in hair cell regeneration. I will specifically examine supporting cells in the avian cochlea which give rise to new hair cells without dividing. I hypothesize that these cells do so by following patterns of gene expression also used during normal development: that the supporting cells, in effect, de-differentiate into a developmentally immature precursor cell which the re-differentiates into a new mature hair cell. I will test this hypothesis by comparing patterns of gene expression during this non-mitotic regeneration to patterns seen in the normal development of supporting and hair cells. In a second project, which will form the major technical training component of this grant, I will identify the nicotinic acetylcholine receptor genes expressed in the normal chick cochlea, the developing chick cochlea, and the regenerating chick cochlea, using rt-PCR and in situ hybridization techniques. Understanding efferent synaptogenesis is important to a complete understanding of the processes of development and regeneration. I will supplement my research training with formal coursework in statistics, development, neuroscience and molecular biology. The Division of Otolaryngology at Boston Children's Hospital is an ideal environment for this training because of the strong departmental support for my career development and because of the availability of outstanding mentors within the institution and within the larger Boston scientific community.